Text ( visual ) : unmediated Acquisition of marine surveying technologies, Addis Ababa : report of the Expert Group Meeting on Acquisition of Marine Surveying Technologies, Addis Ababa, 19-23 October 1987 / Department of International Economic and Social Affairs ; organized in co-operation with the Economic Commission for Africa. -- pbk.. -- New York : United Nations , 1988. -- v, 176 p. : ill., maps ; 28 cm. -- Includes bibliographies ; ST/ESA/202 ; E.88.II.A.19. -- ISBN 9211043034 ; (BA06744605) ; https://ci.nii.ac.jp/ncid/BA06744605 Author Heading(s): United Nations. Dept. of International Economic and Social Affairs ; United Nations. Economic Commission for Africa ; Expert Group Meeting on Acquisition of Marine Surveying Technologies